Recently in some LFS I have seen a different brand of gravel called CongaRoc, which claims to be an exceptionally clean aquarium gravel. It does come in many colors, and from what I understand it is epoxy-free. I have found very little information online about this gravel (it's similar in price to Top Fin, et al), but it sounds more natural and thus seems to me to be a better idea for the fish. Does anyone here have experience with CongaRoc?

Yes, the package claims it has been so throughly pre-washed that it does not need to be washed before you put it in the tank. Obviously, I'd wash it first anyway...

The claim I read is that epoxy coating gravel makes it inert so that it will not alter the water quality. One of my friends with a PhD in Chemistry tells me that epoxy tends to have a lot of leftover chemicals in it that make the claims of inertness VERY unlikely.